Peter Ridd: Crying Wolf Over The Great Barrier Reef

Date: 12/12/18

Dr Peter Ridd, Australia

The scare stories about the Great Barrier Reef started in the 1960’s when scientist first started work on the reef. They have been crying wolf ever since.

Scientists from James Cook University have just published a paper on the bleaching and death of corals on the Great Barrier Reef (GBR) and were surprised that the death rate was less than they expected because of the adaptability of corals to changing temperatures. It appears as though they exaggerated their original claims and are quietly backtracking. To misquote Oscar Wilde, to exaggerate once is a misfortune, to do it twice looks like carelessness, but to do it repeatedly looks like unforgivable systemic unreliability by some of our major science organisations.

It is a well-known phenomenon that corals can adapt very rapidly to high temperatures and that if you heat corals in one year, they tend to be less susceptible in future years to overheating. It is the reason why corals are one of the least likely species to be affected by climate change, irrespective of whether you believe the climate is changing by natural fluctuations or from human influence.

Corals have a unique way of dealing with changing temperature by changing the microscopic plants that live inside them. These microscopic plants called zooxanthellae give the coral energy from the sun by photosynthesis in exchange for a comfortable home inside the coral. But when the water gets hot, these little plants become effectively poisonous to the coral and the coral throws out the plants turning the coral white – it bleaches. But most of the time the coral will recover from the bleaching. And here’s their trick- they take in new zooxanthellae, that floats around in the water quite naturally, and can select different species of zooxanthellae to be better suited to hot weather. Most other organisms have to change their genetic makeup to deal with temperature changes, something that can take many generations. But corals can do it in a few weeks by just changing the plants that live inside them. They have learnt a thing or two in a couple of hundred million years of evolution.

The problem here is that the world has been completely mislead by scientists about the affect of bleaching and rarely mention the spectacular regrowth that occurs. For example, the 2016 bleaching event supposedly killed either 95%, 50% or 30% of the reef depending upon which headline and scientist you want to believe. But the scientists only looked at very shallow water coral – less than 2 meters below the surface which is only a small fraction of all the coral, but by far the most susceptible to getting hot in the tropical sun. A recent study found that the deep water coral (down to over 40 m) got far less bleaching as one would expect. I estimate that less than 8% of the GBR coral actually died. That might still sound like a lot, but considering that there was a 250% INCREASE in coral between 2011 and 2016 for the entire Southern Zone of the GBR, an 8% decrease is nothing to worry about. Coral recovers fast.

But this is just the tip of the exaggeration iceberg. Some very eminent scientists claim that bleaching never happened before the 1980’s and is entirely a man-made phenomenon. This was always a ridiculous proposition. A recent study of 400-year-old coralshas found that bleaching has always occurred and is no more common now than in the past. Scientist have also claimed that there has been a 15% reduction in the growth rate of corals. However, some colleagues and I demonstrated that there were serious errors in their work and that if anything there has been a slight increase in coral growth rate over the last 100 years. This is what one would expect in a gently warming climate. Corals grow up to twice as fast in the hotter water of Papua New Guinea and the northern GBR than in the southern GBR. I could go on with many more examples.

This unreliability of the science is now a widely accepted scandal in many other areas of study and now has a name. “The Replication Crisis”. When checks are made to replicate or confirm scientific results, it is regularly found that around half has flaws. This is an incredible and scandalous situation and it is not just me saying this – it is the editors of eminent journals and many science institutions. A great deal of effort is now going into fixing this problem especially in the Biomedical Sciences where the problem was first recognised.

But not for GBR science. The science institutions deny there is a problem and fail to correct erroneous work. When Piers Larcombe and I wrote an article to a scientific journal suggesting we needed a little extra checking of GBR science, the response from many very eminent scientists was that there was no need. Everything is fine. I am not sure if this is blind optimism or wilful negligence, but why would anybody object to a little more checking? It would only cost a few million dollars, just a tiny fraction of what the governments will be spending on the reef.

But the truth will out eventually. The scare stories about the GBR started in the 1960’s when scientist first started work on the reef. They have been crying wolf ever since. But the data keeps coming in and, yes, sometimes a great deal of coral dies in a spectacular manner with accompanying media fanfare. It is like a bushfire on land, it looks terrible at first, but it quietly and rapidly grows back ready for the scientists to peddle their story all over again.

Dr Peter Ridd

Dr Ridd was, until fired this year, a Physicist at the James Cook University Marine Geophysical Laboratory.